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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - [mc] Some F64 insns (v_add_f64 etc.) -- negative inline constants are not supported."
href="https://llvm.org/bugs/show_bug.cgi?id=28202">28202</a>
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<th>Summary</th>
<td>[mc] Some F64 insns (v_add_f64 etc.) -- negative inline constants are not supported.
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: AMDGPU
</td>
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<th>Assignee</th>
<td>artem.tamazov@amd.com
</td>
</tr>
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<th>Reporter</th>
<td>artem.tamazov@amd.com
</td>
</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org, nikolay.haustov@amd.com
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<th>Classification</th>
<td>Unclassified
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</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=16583" name="attach_16583" title="00204.tests_tg_gfx7_asm_lit1_bug.06.08.min.v_add_etc_f64--iconst_encoding.zip">attachment 16583</a> <a href="attachment.cgi?id=16583&action=edit" title="00204.tests_tg_gfx7_asm_lit1_bug.06.08.min.v_add_etc_f64--iconst_encoding.zip">[details]</a></span>
00204.tests_tg_gfx7_asm_lit1_bug.06.08.min.v_add_etc_f64--iconst_encoding.zip
Example of failing instruction:
<span class="quote">> v_add_f64 v[0:1], -1, 0</span >
The resulting encoding is always with neg modifier, in spite that we have
suitable negative inline constants.
Note that in the instructions which have both 32- and 64-bit (VOP3) encodings
that would lead to unnecessary usage of VOP3.
Perhaps we need to introduce explicit syntax form of neg modifier which would
allow to distinguish negative constants from neg modifier applied to constant.
Tested with r273139 (git # 4a94acfea8bfd6eb6b5809dd40f03e1fa42e673a)
GFX7 lit tests attached.</pre>
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